Hedge funds bought a net $6.8 billion in U.S. equities last week, the largest single week of purchases in 18 years, according to Kobeissi Letter's analysis of prime brokerage flow data. As a share of the S&P 500's total market capitalization, the buying ranked as the ninth-largest weekly purchase since 2008. The move followed $4.8 billion in purchases the week prior, bringing sustained buying pressure into a second consecutive week.
The scale of the shift lines up with separate prime brokerage data from Bank of America, which separately described the period as its largest hedge fund buying week since 2008 — corroboration from a second major prime broker that this wasn't an isolated or narrowly sourced signal.
A Sharp Reversal From Earlier Caution
The buying wave stands out partly because of what preceded it: hedge funds had meaningfully reduced U.S. equity exposure toward the end of July, making the subsequent two-week reversal a notable swing in positioning rather than a continuation of an existing trend. Goldman Sachs' prime brokerage desk separately reported that global hedge funds increased equity holdings for a second consecutive week during the same stretch, describing the shift as hedge funds buying stocks at their fastest pace in roughly six months.
The timing coincides with a broader risk-on move across U.S. markets, including a week in which the S&P 500 gained 3.6% — its best weekly performance since April — driven in part by softer-than-expected inflation data that reduced near-term concern about further rate hikes.
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Why Hedge Fund Flows Matter as a Signal
Prime brokerage buying and selling data is closely watched because hedge funds tend to move faster and with more leverage than long-only institutional investors, making their flows an earlier — if noisier — read on shifting risk appetite than slower-moving fund flow data from mutual funds or pensions. A reversal of this size, from active de-risking in late July to the largest buying week in nearly two decades within a matter of weeks, suggests professional positioning had become unusually cautious heading into August relative to how the broader market subsequently traded, a gap that historically tends to close through exactly the kind of rapid re-risking seen over the past two weeks.
